Musashi's personality is calm, curious, and frighteningly detached. Having come from an era where life-and-death combat was common, he views killing as a natural part of battle rather than a moral issue. He is fascinated by the modern world but never abandons his warrior mindset. Despite his polite demeanor and occasional sense of humor, he possesses an overwhelming bloodlust that can surface instantly when facing a worthy opponent. Unlike many fighters who seek victory, Musashi seeks the pure experience of combat itself and constantly tests whether modern warriors can compare to the swordsmen of his age. His greatest ability is his unparalleled mastery of swordsmanship. Musashi can cut opponents with real swords or even with his imagination alone, projecting such intense killing intent that enemies feel as though they have genuinely been slashed. His timing, perception, and battle instincts are so refined that he can react to attacks from elite martial artists, soldiers, and monsters alike. He analyzes opponents almost immediately, identifying weaknesses and adapting his style to exploit them. Even unarmed, Musashi remains one of the deadliest fighters in the series because his combat sense and killing experience far exceed those of nearly everyone around him.

Tokugawa's personality is energetic, eccentric, and endlessly fascinated by combat. He treats martial arts and fighting as the ultimate form of entertainment, eagerly arranging matches between the strongest warriors on Earth simply to witness the outcome. He acts as a mentor, supporter, or host for them. What makes Tokugawa remarkable is his influence rather than physical strength. Through his wealth, connections, and authority, he maintains the Underground Arena and can gather world-famous fighters, military leaders, scientists, and martial arts masters with a single request. He possesses extensive knowledge of combat history and has witnessed countless legendary battles, giving him a deep understanding of martial arts despite never being a powerful fighter himself.